Human Defense System Flashcards
What is a pathogen?
A disease causing organism
What is an antigen?
A substance (protein) on the surface of a pathogen, causes lymphocytes (white blood cells) to produce antibodies
What is an antibody?
Proteins produced by lymphocytes in response to an antigen
What is an antibiotic
Chemical produced by micro organisms (bacteria) to kill other bacteria (pathogens)
Do antibiotics work on viruses?
No
What is immunity?
The ability to resist disease
What is a vaccine?
A substance introduced into the body to induce an antibody response leading to immunity
What is vaccination?
The introduction of a non disease causing dose of a microbe to start an active immune response
What is asepsis?
Excluding as many micro organisms/ microbes as possible
What are aseptic techniques?
Techniques used to eradicate microbes e.g. flaming, alcohol
What does sterile mean?
Environment free of life (microbes)
What is induced immunity?
Body contains specific antibodies in response to specific antigens
What is active immunity?
Long term immunity and involves the production of antibodies
Give an example of natural active immunity
Antigen enters the body and white blood cells produce antibodies (get a disease)
Give an example of artificial active immunity
Antigen enters the body by a vaccine and your body produces antibodies
What is passive immunity?
Given made antibiotics
Give an example of natural passive immunity
Antibodies enter via. breast milk or via. placenta
Give an example of artificial passive immunity
Injected with antibodies e.g. tetanus injection
Name three parts that make up the first line of the human defense system?
Skin - physical barrier
Clotting - If the skin is broken, blood clotting prevents entry
Cilia hairs - Prevent entry in respiratory system
Name three parts that make up the second line of the human defense system
- White blood cells called macrophages (phagocytes) go to the site of attack and engulf any pathogen. This process is called phagocytosis. (Prevents pathogens attacking cells).
- Complimentary set of proteins are free in the plasma of the blood destroy pathogens as they move to the site of infection.
- Cells that are infected by viruses produce a protein called interferons which covers neighbouring cells preventing viral multiplication.
What is the specific defense system
Attacks specific pathogens due to their antigens
Works by the production of antibodies
What are the two types of antibodies?
Monocytes and lymphocytes
Where are monocytes made?
In the bone marrow
Where do monocytes mature?
Macrophages
Where do monocytes move to?
Move in plasma or fixed in spleen or lymph nodes
What do monocytes do?
Engulf pathogens
Where are lymphocytes made?
Made in bone marrow
Where are B lymphocytes made?
Made in the bone marrow
Where do B lymphocytes mature?
Mature in bone marrow/ lymph nodes
Where do B lymphocytes move to?
Move to spleen, lymph node
What do B lymphocytes do?
Recognise a specific antigen on a pathogen and produce a specific antibody.
Macrophages engulf and stop the infection
Where are T lymphocytes made?
Made in the bone marrow
Where do T lymphocytes mature?
Mature in thymus
Do T lymphocytes produce antibodies?
No
What switches on T lymphocytes?
The general defense system
What is the function of helper T cells?
Activates B lymphocytes to replicate
Activate T-killer cells and T suppressor cells
What is the function of T killer cells?
Destroy cells infected by the virus/pathogen
Destroy foreign bodies e.g. organ transplants
Produce a chemical called perforin
What is the function of T suppressor cells?
Infection is over
Prevents the immune system and T killer cells from destroying all cells
What is the function of T memory cells?
Long lived in the circulatory system
Help the immune system to react quicker if infected again by the same antigen (immunity)
